The subject matter disclosed herein relates to a cast shell for steam turbine systems. Specifically, the subject matter disclosed herein relates to a high or intermediate-pressure portion of a cast shell for a steam turbine system, the high or intermediate-pressure portion of the shell having a portion including an oblate spherical cross-section.
Steam turbine shells are components that encompass, for example, the high pressure (HP) and/or intermediate pressure (IP) sections of the steam turbine. In practice, steam turbine shells hold the stationary steampath components in close proximity to the rotating steampath components. Nozzle connections included in the structural shell allow for the entry and exit of the working fluid (e.g., steam) from the shell. In addition, several portions of the shell are configured and contoured to provide efficient flow path transitions between the nozzles and steampath components. Traditional steam turbine shells include both inlet (or admission) sections and exhaust (or extraction) sections having a substantially concentric-shaped channel configured to surround a portion of the steampath sections of the turbine. The different sections of the combined turbine shell (e.g., HP, IP, etc.) will have differing volumes and cross-sectional sizes.